It is current practice to mount power fuses used in conjunction with power distribution circuits within a metal enclosure having hinged access doors. In such structures, fuses and other live electrical components may be mounted behind a dead front wall which isolates the human operator from these components when they are energized. Such devices in the prior art are represented by the disclosure in U.S. Pat. No. 4,250,357 wherein a fuse isolating wall is provided inside a metal housing structure and is located immediately behind the housing doors. Fuse panels are hingedly mounted to the isolating wall and constitute parts thereof so that a fuse mounted or fuse mounting insulating structure secured to the interior of each fuse panel is isolated from access by an operator so long as the panel is in its normal position forming a part of the insulating wall. Conducting means preferably in the form of a bushing having a conventional bushing well extends through the fuse panel and is interconnected with one terminal of the fuse on the inside of the fuse panel while a part of the conducting structure extends outside the fuse panel and is arranged for disjointable engagement with connecting means such as a circuit elbow connector. The fuse panel is held in its normal position as a part of an isolating wall by latch means and such latch means is held in its latching position by an interlock movably mounted on the fuse panel. Portions of the interlock operating lever are interposed between the fuse panel and the disjointable connector. When it is desired to replace a fuse, the disjointable connecting means is removed from its associated conductor and the interlock operating lever is moved to its latch releasing position following which an operating rod is used to engage the latch and to rotate it to its unlatched condition. The fuse panel is then swung out of its position as a part of the isolating wall and may then be removed therefrom to a convenient location for the replacement of the fuse. Thereafter the procedure is reversed to reinsert the replacement fuse into the circuit.
One problem inherent with this type system is that the human operator may be required to use a 10 to 14 foot long "hook stick" to open or close the mounting assembly. A force of above 50 lbs. may be required to lift the assembly to begin movement thereof to a closed position, thus requiring considerable strength from an operator using a "hook stick". Conversely, when opening the assembly, if the "hook stick" slips for any reason the door and fuse can slam down to the open position causing severe damage or destruction to the mounting plate and high voltage fuse. This is particularly hazardous when glass tube current limiting fuses are used.
Another problem is isolation of the components within the fuse compartment when the fuse mounting door is open. Prior U.S. Pat. Nos. 4,827,374 and 4,463,227 have each dealt with the problem, however neither has provided a totally satisfactory solution. Consequently there remains a need for an assembly that controls the descent of a fuse mounting plate as it is opened and a mechanism for simultaneously isolating the fuse mounting assembly from the fuse compartment.